DevOps, CI/CD and Automation

How can I convert an XMLType variable to a Varchar2 variable.
I am doing the following.

DECLARE v_xml XMLType;
v_value varchar2(200);

BEGIN

SELECT XMLELEMENT("Phone",'9999999999')
INTO v_xml
FROM Dual;

END;

I need to convert the value of v_xml to varchar2 and display using DBMS_OUTPUT.PUT_LINE.

Thanks
RK